The program of research of the Environmental Health Sciences Center is concerned with the toxicology and biological effect of environmental chemicals including pesticides, industrial chemicals, and chemicals of natural occurence. Specific examples include pentachlorophenol, phenoxy phenols, organophosphates, phenoxy acetic acids, bis halogenated phenols, hydrazine, and heavy metals such as mercury, cadmium, and arsenic. Investigations include research on oncogenicity, mechanisms of toxic effect, immunological responses of organisms to the chemicals, modeling and physico-chemical aspects of routes and rates of exposure. The Center program involves coordination of research for long-term projects on the environmental toxicology, pilot or feasibility projects, provision of special equipment, facilities, services, and administration. Examples of activity under the Center program includes covalent binding of toxicants, membrane effects, interaction of environmental chemicals with oncogenic viruses, photochemistry and mathematical and statistical modeling of pharmacodynamic and toxicological effects. Additionally, efforts are directed toward identification of emerging environmental problems of health significance and undertaking of studies to determine alternative solutions to problems.